Circuit breaker with lost motion lockout member for interposing between contacts



March 28, 1967 T. VCW. .BUTLER ETAL 311725 CIRCUIT BREAKER WITH LOST MOTION LOCKOUT MEMB FOR INTERPASSING BETWEEN CONTACTS Filed oct. 2s, 1965 2 sheets-sheet 1 l .L- gl p March 28, 1967 T. w. BUTLER ETAL 3,311,725

CIRCUIT BREAKER WITH LOST MOTION LOCKOUT MEMBER FOR INTERPASSING BETWEEN CONTACTS Filed. Oct. 25, 1965 2 Sheets-Sheet 2 Vif ya v w# El ENTOR,

United States Patent O 3,311,725 CIRCUIT BREAKER WITH LOST MOTION LOCK- OUT MEMBER l y FOR INTERPOSING BETWEEN CONTACTS Y This invention relates generally to circuit breakers and more particularly .to an improved manual operator and lockout mechanism for a manual reset circuit breaker.

A need has developed for an improved, relatively small, manually operable circuit breaker useable for the protection of relatively low current devices, for example, food waste deposers, electric hand tools, food mixers, meat grinders, blenders, etc. Such a motor protector must provide on-off operation, locked rotor protection, and overload protection for such devices.

Accordingly, one object of the instant invention is an improved circuit breaker. I

Another object is an improved manual operator and lockout mechanism for a manually operable circuit breaker.

IOther objects and advantages of the instant invention will be apparent in the following specification, claim and drawings, wherein: f

FIGURE 1 is a top view of a circuit breaker in accordance with an exemplary constructed embodiment of the instant invention with the cover removed;

FIGURE 2 is a fragmentary view of the improved manual operator and lockout mechanism taken substantially within the circle 2 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken substantially along the line 3-3 of FIGURE l;

FIGURE 4 is a view taken in lthe direction of the arrow 4 of FIGURE 2;

FIGURE 5 is a view similar to FIG. 1 showing the manual operator and separable contacts locked in the open condition, and

FIGURE 6 is a cross-sectiona-l view taken substantially along the line 6 6 of FIGURE 5.

A circuit breaker in accordance with the instant invention features a manual operator having a lockout mechanism pivotally secured thereto by a lost motion connection. The lockout member comprises a pivoted spring biased insulating member that is interposed between a fixed contact and a movable contact mounted on a snapacting bimetallic blade. The lockout member has a cam thereon that is engageable with a snap-acting blade upon pivoting of the lockout member. The lockout member maintains the contacts of the circuit breaker in the disengaged condition upon manual operation or upon the occurrence of a predetermined temperature or electrical condition. The manual operator is movable to a reset conditio-n to re-energize an electrical circuit containing the circuit breaker.

More particularly, as best seen in FIG. 3, an improved circuit breaker 10 comprises insulating upper and lower casings 12 and 14 that a-re retained together as by rivets 18. As seen in FIG. 1, a threaded ferrule 2t)` extends into the casing 14 to facilitate attachment of the circuit 10 to a panel board or the like.

As best seen in FIGURE 1 of the drawings, a pair of terminals 30 and 32 extend through complementary apertures in the casing 14 for connec-tion to an electrical circuit. A fixed contact 40 is secured to an inner end portion 42 of the terminal 30 in alignment with a movable contact 44. The movable contact 44 is supported on a free end 46 of a snap-acting bimetallic blade 48. The

blade 48 has a non-developable surface 50 therein, a fixed end 52 thereof being supported by an inner end 54 of the terminal 32. y

An insulating, manual operator 60 has a Astem portion 62 to facilitate manual operation and is slidably mounted for movement in a complementary recess `64 in the casing 14. The manual operator 60 has a channel 66 therein that accepts an operating spring 68. The spring 68 is seated in a complementary seat 69 in the case portion 14 and normally biases the manual Ioperator downwardly, as seen in FIGURE 1, to the contacts open condition.

In accordance with the instant invention an insulating llockout member 70 is pivotally supported on a pin 72 on the manual operator The lockout member is normally biased counterclockwise, as seen in the drawings, against a shoulder 73 on the manua-l operator I60 by a spring 74. The lockout member 70 carries a cam 76 that is engageable with the blade 48 after'the first increment of rotation of the lockout member 70 to bias the blade 48 upwardly.

As best seen in FIGURES 5 and 6 of the drawings, movement of the manual operator` 60 downwardly brings the cam portion 76 on the lockout member 70 into a rotating, camming, engagement with the snap-acting bimetallic blade 48. Continued movement of the manual operator 60 downwardly, as seen in FIGURES 1 and 5 of the drawings, effects a loading of the spring 74 which subsequently effects a rapid camming of ythe blade 48 upwardly t-o the contacts open condition. Thus, quick opening of the contacts 40 and 44 is effected even though the manual operator 60 might be slowly retracted or teased to the open condition.

It is to be noted, as seen in FIG. 6 of the drawings, that the blade 48 maintains its bias towards the contacts closed condition upon movement of the cam 76 thereunder due to manual opening of the circuit breaker. Thus, movement of the manual operator 60 upwardly to the contacts closed condition effects closure of the contacts 40l and 44 under the spring bias of the blade 48.

It is also to be noted that the lockout member 70 is normally positioned against the movable contact 44 thereby to rest-rain movement of the manual operator 60 downwardly to the contacts open condition when the contacts 40 and 44 are closed. Upon opening of the contacts 40 and 44, due to a predetermined electrical condition in an electrical circuit containing the circuit breaker 10, the lockout member 70` moves between the contacts 40` and 44 to the position illustrated in FIGS. 5 and 6.

From the foregoing description it should be apparent that the pivoted lockout member 70 having a cam 7:6 thereon is connected to the manual operator 60 by.a lost motion connection that both provides a mechanical advantage which enables the contacts 40 and 44 to be manually opened with minimum effort and effects snap opening of the contacts 40 and 44. Opening of the contacts due to manual operation of the manual operator 60 is effected with a snap action since the spring 74 is loaded upon initial movement of the manual operator 60 towards the contacts open condition tending to subsequently drive the cam 76 under the blade 48 with a snap action. The cam 76y is normally held out of engagement with the blade 48 since the lockout member is directly engaged with the movable contact 44.

It is also to be noted that since the manual operator 60 does not control opening of the blade 48 due to an overload or short circuit condition. Therefore the circuit breaker 10` is trip-free in operation.

It is to be understood that the improved construction of the circuit breaker herein disclosed and described is presented for the purpose of explanation and illustration and is not intended t-o indicate limits of the invention the scope of which is defined by the fol-lowing claim.

. 3 What is claimed is: A manually openable and closeable circuit breaker comprising:

an insulating enclosure,

a pair of terminals extending exteriorly of said casing,

a Xed Contact mechanically supported by and electrically connected to one of said terminals,

a snap-acting bimetallic blade having a fixed end portion mechanically supported by and electrically connected to the other of said terminals,

a movable contact on the other end of said blade engageable with said fixed contact,

a manual operator having a handle portion extending exteriorly of said enclosure,

a generally flat lockout member pivotally secured to said manual operator,

a manu-al operator spring normally biasing said manual operator and lockout member towards the contacts open condition,

a lockout spring normally biasing said lockout member for rot-ation relative to said manual operator, said lockout member being normally engagedy with said movable contact to preclude movement of said manual operator to the contacts open condition and t0 preclude interposition of said lockout member between said contacts, thereof,

a cam on said lockout member engageable with said blade upon rotation of said lockout member for biasing said blade towards the contacts open condition,

the pivotal relationship between said manual operator and the lockout member thereof effecting a lost motion connection therebetween whereby the cam on said lockout member is engaged with said blade while said contacts are in the closed condition and said lockout spring is loaded to bias said cam under said blade with a snap action.

No references cited.

BERNARD A. GILHEANY, Primary Examiner.

20 H. A. LEWITTER, Assistant Examiner. 

